The importance and usage of the computer mouse and trackball input devices have become nearly equivalent to that of the computer keyboard itself. With the popularity of electronic design tools, graphical user interfaces, and even computer games, at least one or both of these input devices have now become standard equipment assumed to be attached to every computer. In fact, research directed by Peter W. Johnson of University of California Berkeley/San Francisco Ergonomics Lab indicates that mouse usage occupies one to two-thirds of one's working time on a computer. Early mouse and trackball designers, however, did not contemplate the adverse physical affects of this prolonged and repetitive use of their devices. Neither did they design their products to accommodate the reality of users having widely varying hand sizes and a preferred hand with which they operate the device.
Specifically in the case of the computer mouse, there are numerous design flaws that can lead to a variety of repetitive stress disorders such as the widespread carpal tunnel syndrome (CTS). For example, even the latest "ergonomic" designs demand a hand, wrist and arm position significantly inferior to the preferred neutral position (i.e. with the palm surface vertical). These designs also make the user susceptible to unnatural lateral, instead of flexing, wrist movements to control the cursor position. Further, the user must constantly be grasping the mouse with at least two fingers when moving the cursor or even actuating the mouse buttons, adding further fatigue. All designs, too, tend to forget about the thumb which is usually left to be dragged back and forth across the work surface or under the stress of constantly being held clear of the surface by the user. Actuating the mouse buttons causes additional stress since they are usually placed in such a way as to require the unnatural movement of the user's fingers in a direction away from the thumb. Though many devices boast universality, few can comfortably accommodate both left and right handed users and more than a narrow range of hand sizes. Finally, the devices are typically made of hard plastic causing further discomfort. Note, that many of these same design shortcomings also exist with the trackball devices presently available.
Thus, as the computer mouse and track ball continue to be heavily used in record numbers of homes and businesses, there is a great need to make a paradigm shield from the conventional mouse/trackball design to an input device design that is truly ergonomic and universal, yet has all the control and functionality to which computer users have grown accustomed.